Use Kopano with existing mail server

I have a mail server and would like to use kopano primarly for Exchange support and the calendar and address book features. Is there a way to download and send mails with pop3/imap/smtp from my existing mail server to Kopano?

Is there a way to download and send mails with pop3/imap/smtp from my existing mail server to Kopano?

you could use something such as fetchmail/getmail to pull external mails into the Kopano mailstore. There does not exist a way to simply display external mail, without them being in the Kopano mailbox.